Patent GB-582438-A (GB)
Title: Method of transferring photographic emulsion layers from one support to another and apparatus suitable therefor
IPC: G03C7/20
Filed: 1944-05-30
Abstract: 582,438. Colour photography. KODAK, Ltd. May 30, 1944, No. 24783/45. Convention date, May 27, 1943. Divided out of 582,436. [Class 98 (ii)] In a method of stripping a photographic emulsion layer from one perforated film strip and transferring it to another similarly perforated film strip, the two film strips are registered by means of their perforations with the emulsion to be transferred between them, pressed into contact, re-registered after the pressing, maintained under tension and in registry until they are firmly adhered together, and then separated with transfer of the emulsion layer from one strip to the other. The registration and re-registration may be performed while the films are in an aqueous bath, and the films after registration and re-registration may be caused to pass over an extended path while in contact before stripping. The stripping and transfer may be performed in apparatus having a film sprocket with two series of teeth, one dimensioned to fit one set of film perforations transversely and the other adapted to engage another set loosely, means for guiding the two films on to the sprocket, means for positioning the films in contact on the teeth whereby they are registered accurately by the transversely fitting teeth, means for drawing the films from the sprocket under tension, means for pressing the films firmly together after they have been drawn from the sprocket, a second sprocket similar to the first for re-registering the films accurately after they leave the pressing means and while still under tension, and means for maintaining the films in contact over an extended path and for stripping them apart. As shown in Fig. 2, an unsensitized perforated strip F and an exposed perforated multilayer film F<1> (which may be as described in Specification 574,137 are passed through a humidifying chamber 11 and then are drawn into a wetting tank 28 over suitable pulleys by sprocket 41 and first come together on sprocket 80 which is braked by a smoothacting friction brake. The films are brought into longitudinal registry while passing over sprocket 80, and then pass between presser rolls 95, 96 and then over a sprocket 100 which brings the perforations into exact registry along at least one edge. The distance between sprockets 100 and 41 must be such as to permit good adhesion to develop. The sprocket teeth along one side fill the perforations transversely precisely and on the other side only loosely. The wide sprocket teeth are always on the same side of the multilayer film, e.g. the sound track side. With rounded side perforations, a weak forward frictional drive is maintained on sprocket 100. The tank 28 may contain water or aqueous ethyl alcohol and contains a scrubber roller as described in Specification 582,436. As shown in Fig. 4, the teeth of the sprocket 80 extend through slots 83 in the member 84, and the floating member 86 is resiliently pressed towards member 84 by the spring 88. The member 84 acts as a stripper plate and is undercut at 85 to prevent scratching. The shaft of sprocket 41, Fig. 2, is chain-driven, and carries a pulley connected by a belt to a pulley on the. shaft of sprocket 100, which is friction driven from the shaft. A weighted brake band is applied to a sleeve on the shaft of sprocket 80 to provide tension on the films between sprockets 80 and 41. The film F passes to sprocket 80 from roller 40 and the film F from roller 31, a stream of water being directed between the films as they approach sprocket 80. One or other of the films may be stretched before bonding by adjustment of the bracket carrying the rollers 31 and 40. The bonded films pass between squeegees removing surplus liquid on leaving tank 28 and then pass over roller 43 and are spirally wound round rollers in the drying chamber in which the stripping is effected as described in Specification 582,436. Stripping of the second emulsion layer is performed in a similar manner. Specifications 574,164 and 582,439 also are referred to.